1. Field of the Invention
This invention relates to both means for and methods of preparing an improved supportive wrapping for surgical supports or the like and, more specifically, to a unique, immobilizing and/or protective body support or cast comprised of a bandage material impregnated or coated with a crystallized polyurethane polymer, preferably, formed directly on the bandage material and which is specially prepared to render desired handling and use properties previously unavailable when employing prior art surgical support or orthopedic cast techniques.
2. Description of the Prior Art
The traditional surgical support or body cast for immobiliztion and/or protection of an afflicted portion of the body during healing is a gauze and plaster of Paris composite. Some of the well known shortcomings of this traditional approach involve heaviness, bulkiness, water sensitivity, dust collection, lack of transparency to X-rays, difficulty of removal, lack of flexibility and discomfort of exothermic heat evolved during drying of the cast. These and other shortcomings have led to the proposal of surgical supports or body casts composed of other materials or combinations of materials. In particular, with the advance of polymer technology, much attention has been given to the effective utilization of plastics to overcome the deficiencies of the plaster of Paris cast.
One approach that has been taken in utilizing plastics technology is disclosed in U. S. Pat. No. 3,302,642. As therein disclosed, it is proposed to extrude a net-like polymer fabric, specifically, a vinylidene chloride polymer fabric, wind the fabric on a spool and supercool the entire spool with the wound material thereon before crystallization or substantial crystallization can occur. When supercooled to temperatures down to -100.degree. C, the polymer fabric can be maintained without significant crystallization for a period of 2 weeks or more. For application or use, the polymeric fabric is allowed to warm to room temperature until pliable. Then it is cut to the desired shape and applied to the patient by wrapping. The loose ends are weakly held together with clips or stitches or other fastening means. Within 10 to 20 minutes at room temperature, the polymeric fabric will crystallize and stiffen sufficiently to provide a surgical or body support.
Another approach, claiming similar utility to the foregoing, is disclosed in U.S. Pat. No. 3,728,206. In accordance with this latter disclosure, it is proposed to provide a composite, supportive non-thermoplastic foam web impregnated with a matrix of foam-like thermoplastic material which, upon heating, can be readily molded to an injured limb and, thereafter, allowed to cool, crystallize and harden to form an orthopedic bandage or wrap. However, since this approach, like the prior approach, is based upon providing a premanufactured product of limited shelf life because of the nature of the thermoplastic matrix materials disclosed, special packaging arrangements, the addition of chemical stabilizers and special handling conditions are proposed or found essential to preserve the useful life of the product for any appreciable period of time. Notwithstanding, as distinguished from the prior disclosure wherein clips, stitches or the like are required for weakly holding loose ends of the bandage together, the thermoplastic matrix of the bandage of this latter disclosure is generally cohesive at the elevated temperatures of application to the patient and, accordingly, provides a self-adhesive bandage.
Some other approaches that have been taken in utilizing plastics technology are disclosed in U.S. Pat. Nos. 2,301,426, 2,375,365, 2,483,715, 2,582,242, 2,616,418, 2,759,475, 2,800,129, 3,420,231, 2,467,086, 3,490,444, 3,501,427, 3,592,190, 3,656,476, 3,674,021, 3,692,023, 3,763,858;and British Pat. No. 1,155,556, the disclosures of which, like those of the aforementioned patents, are incorporated herein by reference.
Generally, the development of the state of the art of plastic supports has heretofore found limited acceptance because of the presence of one or more deficiencies, including: use of solvents that are potentially toxic, air polluting, deleterious to the skin or inflammable; deficiencies in desired physical and/or chemical properties; lack of rigidity, insufficient rigidity or insufficient flexibility in the support; difficulties in handling, preparation, use and limited shelf life; the presence of exothermic heat during curing or polymerization; inflexibility in use or application due to the properties of materials being inexorably fixed during premanufacture and, also, attendant limitations on the shape or form of materials made available as premanufactured products. Accordingly, there is a need for improvements in the application of polymer technology to the field of orthopedic supports and body casts.